• Title/Summary/Keyword: Mass changes

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A Study on Changes in Antibacterial Activity of Pepsin-hydrolyzed Bovine Apo-lactoferrin at Various Method for Pasteurizations and pH Values (살균방법 및 pH 조건에 따른 Pepsin-hydrolyzed Bovine Apo-lactoferrin의 항균성 변화에 관한 연구)

  • 김종우;이조윤;금종수;유대열
    • Food Science of Animal Resources
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    • v.18 no.2
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    • pp.157-163
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    • 1998
  • This study was carried out to examine that pepsin-hydrolyzed bovine lactoferrin has applicabilities which are market milk and dairy products. The stability of pepsin-hydrolyzed bovine apo-lactoferrin and the change of its antibacterial character has been studied under various method for pasteurization (LTLT; 65$^{\circ}C$ / 30min., HTST ; 75$^{\circ}C$ / 15sec., UHT ; 135$^{\circ}C$ / 3sec.) and pH Values (pH 2.0, pH 4.0, pH 6.8). The ehated samples were assayed for minimal bacteriocidal concentrations (MBCs) and bacteriocidal effect against E. coli. The results obtained were summarized as follows: After fractionation of pepsin-hydrolyzed bovine lactofeerin by gel filtration. several peptide fractions were found that had strong antibacterial activity. SDS-PAGE showed that the one of these fractions with strong antibacterial activity, which had a molecular mass a range of 30∼33KDa. The MBCs for pepsin-hydrolyzed bovine lactoferrin fraction No. 2 against E. coli required to cause complete inhibition of growth varied within the range of 200∼400 $\mu\textrm{g}$/ml, depending on heat treatments and pH conditions. The peptide fraction No. 2 showed strong bacteriocidal activity against E. coli at LTLT and HTST treatments under acidic pH conditions. and was reduced activity at UHT treatment under pH 6.8 condition.

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Effects of a Primary Healthcare Post Obesity Management Program for Middle-Aged Obese Women Living in Rural Areas (농촌 거주 중년 비만여성을 위한 비만관리 프로그램의 효과)

  • Park, Chun Im;Woo, Jin Ju
    • Journal of Korean Academy of Rural Health Nursing
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    • v.11 no.1
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    • pp.15-22
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    • 2016
  • Purpose: The purpose of this study was to analyze changes in body weight (kg) and body mass index (BMI) in middle-aged women following a 12 week exercise program. Methods: The obesity management program for primary health care posts, which consists of exercise therapy and dietary counseling, was provided for obese women aged 40 to 64 (N=15). General characteristics of the women and differences in body weight and BMI before and after the program were analyzed using SPSS 22.0. Results: The major findings of this study are as follows; Average body weight before the program was 65.7 kg, and it was significantly reduced to 63.9 kg after the program (z = -3.41, p = .001). The average level of BMI decreased considerably from 27.9 kg/m2 to 27.2 kg/m2 (z = -3.41, p = .001). Conclusion: The findings from this study show a significant decrease in body weight and BMI after the program. Continuous study is needed to develop a variety of obesity management programs for middle-aged obese women. When developing programs regional characteristics need to be considered and there is a need to confirm the effectiveness of the programs.

The Effect of Shift Work on the Diurnal Rhythm of Blood Pressure in Nurses (간호사의 야간교대근무로 인한 혈압의 일중 변동 양상)

  • Lee, An-Saeng;Rhee, Sang-Jae;Kim, Nam-Ho
    • Korean Journal of Occupational Health Nursing
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    • v.18 no.1
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    • pp.14-21
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    • 2009
  • Purpose: This study was performed to investigate the effect of shift work on diurnal blood pressure (BP) pattern in nurses. Method: We studied 20 healthy nurses engaged in 3 shift work. 24-hour ambulatory BP monitoring was performed to each nurse two times during the day and night shift. Five nurses were excluded because of inadequate BP measurement. Results: All subjects were female. The mean age was 27.4 years (range: 23-33 years) and mean body mass index was 19.7 Kg/$m^2$ (range: 18.0-21.2 Kg/$m^2$). The changes of systolic BP ($17.8{\pm}9.1$ vs. $13.2{\pm}4.7%$, p=0.031), diastolic BP ($22.3{\pm}8.7$ vs. $17.3{\pm}9.0%$, p=0.061), and heart rate ($25.2{\pm}5.2$ vs. $12.5{\pm}8.7%$, p=0.001) during the sleeping period were decreased after a night shift compared with day shift. The non-dipper group significantly increased from 20% to 40% after a night shift (p=0.018). Conclusion: Working night shift is significantly associated with non-dipper status in nurses.

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Experimental Study on the Characteristics of Heat Exchanger of 1 kW PEMFC System for UAV (무인항공기용 고분자전해질형 연료전지 시스템의 열교환기 성능 특성 연구)

  • Kang, Sang-Gyu;Kim, Byung-Jun;Kim, Han-Seok
    • Journal of Hydrogen and New Energy
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    • v.22 no.6
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    • pp.819-826
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    • 2011
  • The proton exchange membrane fuel cell (PEMFC) is regarded as the most promising alternative power sources for unmanned aerial vehicle (UAV) due to its high energy density and silent operation. Since there are many load changes during UAV flight, thermal management is one of the important factor for the performance of PEMFC. In order to reduce the UAV weight for the stable operation of UAV, thermal management system (TMS) studied in this work does not use the fan but use the air flowing into UAV by UAV flight. In order to develop the passive type heat exchanger (HEX) for 1kW PEMFC, four types of HEXs are fabricated and their cooling performances are compared. The parametric study on the cooling performance of HEXs has performed with the variation of operating parameters such as mass flow rates and inlet temperature of air and coolant. Type 4 has the best performance in every case. This study can be helpful to achieve the optimal design of HEX for PEMFC powered UAV.

Engineering behavior of expansive soils treated with rice husk ash

  • Aziz, Mubashir;Saleem, Masood;Irfan, Muhammad
    • Geomechanics and Engineering
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    • v.8 no.2
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    • pp.173-186
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    • 2015
  • The rapid urbanization in Pakistan is creating a shortage of sustainable construction sites with good soil conditions. Attempts have been made to use rice husk ash (RHA) in concrete industry of Pakistan, however, limited literature is available on its potential to improve local soils. This paper presents an experimental study on engineering properties of low and high plastic cohesive soils blended with 0-20% RHA by dry weight of soil. The decrease in plasticity index and shrinkage ratio indicates a reduction in swell potential of RHA treated cohesive soils which is beneficial for problems related to placing pavements and footings on such soils. It is also observed that the increased formation of pozzolanic products within the pore spaces of soil from physicochemical changes transforms RHA treated soils to a compact mass which decreases both total settlement and rate of settlement. A notable increase in friction angle with increase in RHA up to 16% was also observed in direct shear tests. It is concluded that RHA treatment is a cost-effective and sustainable alternate to deal with problematic local cohesive soils in agro-based developing countries like Pakistan.

Indirect structural health monitoring of a simplified laboratory-scale bridge model

  • Cerda, Fernando;Chen, Siheng;Bielak, Jacobo;Garrett, James H.;Rizzo, Piervincenzo;Kovacevic, Jelena
    • Smart Structures and Systems
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    • v.13 no.5
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    • pp.849-868
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    • 2014
  • An indirect approach is explored for structural health bridge monitoring allowing for wide, yet cost-effective, bridge stock coverage. The detection capability of the approach is tested in a laboratory setting for three different reversible proxy types of damage scenarios: changes in the support conditions (rotational restraint), additional damping, and an added mass at the midspan. A set of frequency features is used in conjunction with a support vector machine classifier on data measured from a passing vehicle at the wheel and suspension levels, and directly from the bridge structure for comparison. For each type of damage, four levels of severity were explored. The results show that for each damage type, the classification accuracy based on data measured from the passing vehicle is, on average, as good as or better than the classification accuracy based on data measured from the bridge. Classification accuracy showed a steady trend for low (1-1.75 m/s) and high vehicle speeds (2-2.75 m/s), with a decrease of about 7% for the latter. These results show promise towards a highly mobile structural health bridge monitoring system for wide and cost-effective bridge stock coverage.

Vibration control of a time-varying modal-parameter footbridge: study of semi-active implementable strategies

  • Soria, Jose M.;Diaz, Ivan M.;Garcia-Palacios, Jaime H.
    • Smart Structures and Systems
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    • v.20 no.5
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    • pp.525-537
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    • 2017
  • This paper explores different vibration control strategies for the cancellation of human-induced vibration on a structure with time-varying modal parameters. The main motivation of this study is a lively urban stress-ribbon footbridge (Pedro $G\acute{o}mez$ Bosque, Valladolid, Spain) that, after a whole-year monitoring, several natural frequencies within the band of interest (normal paring frequency range) have been tracked. The most perceptible vibration mode of the structure at approximately 1.8 Hz changes up to 20%. In order to find a solution for this real case, this paper takes the annual modal parameter estimates (approx. 14000 estimations) of this mode and designs three control strategies: a) a tuned mass damper (TMD) tuned to the most-repeated modal properties of the aforementioned mode, b) two semi-active TMD strategies, one with an on-off control law for the TMD damping, and other with frequency and damping tuned by updating the damper force. All strategies have been carefully compared considering two structure models: a) only the aforementioned mode and b) all the other tracked modes. The results have been compared considering human-induced vibrations and have helped the authors on making a decision of the most advisable strategy to be practically implemented.

Development Communication Approaches to Community Development and Adult Education (지역사회개발과 사회교육을 위한 개발커뮤니케이션 접근)

  • Chun, Eun-Kyung;Kim, Sung-Soo
    • Journal of Agricultural Extension & Community Development
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    • v.7 no.2
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    • pp.359-376
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    • 2000
  • The purposes of this exploratory study were to interrelate the scholastic discipline of the ‘development communication’ into ‘community development’ and ‘adult education’ in terms of interests, views and theoretical backgrounds of these fields of social sciences; and to draw some implications for developing scholastic interactions among these fields to pursue common social changes of human society. Development communications provide opportunities to set goals, to decide contents, and to utilize communication media in developmental efforts. Contemporary trends of development communication, community development and adult education are concerned with indigenous, two-way, bottom-up and people-centered communication from exogenous, one-way, top-down and institution-centered communication of the past. Multidisciplinary approaches to communication concepts and methodology may increase the potentials of community development and adult education in terms of efficiency and effectiveness. Some of the development communication approaches such as traditional and folk media approach. new media or ICT(information & communication technology) approach, participatory communication for development approach, communication support development approach and mass media approach may be applicable for community development and adult education. Better understanding on development communication approaches will be needed for the adult educators as well as community development practitioners.

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Development of particle focusing device to monitor various low pressure processes (다양한 조건의 저압 공정 모니터링을 위한 입자 집속 장치 개발)

  • Kim, Myungjoon;Kim, Dongbin;Kang, Sang-Woo;Kim, Taesung
    • Particle and aerosol research
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    • v.13 no.2
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    • pp.53-63
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    • 2017
  • As semiconductor process was highly integrated, particle contamination became a major issue. Because particle contamination is related with process yields directly, particles with a diameter larger than half pitch of gate should be controlled. PBMS (Particle beam mass spectrometry) is one of powerful nano particle measurement device. It can measure 5~500 nm particles at ~ 100 mtorr condition in real time by in-situ method. However its usage is restricted to research filed only, due to its big device volume and high price. Therefore aperture changeable aerodynamic lenses (ACALs) which can control particle focusing characteristics by changing its aperture diameter was proposed in this study. Unlike conventional aerodynamic lenses which changes particle focusing efficiency when operating condition is changed, ACALs can maintain particle focusing efficiency. Therefore, it can be used for a multi-monitoring system that connects one PBMS and several process chambers, which greatly improves the commercialization possibility of the PBMS. ACALs was designed based on Stokes number and evaluated by numerical method. Numerical analysis results showed aperture diameter changeable aerodynamic lenses can focus 5 to 100 nm standard particles at 0.1 to 10 torr upstream pressure.

Modeling of Space Shuttle Main Engine heat exchanger using Volume-Junction Method (Volume-Junction Method를 이용한 우주왕복선 액체로켓엔진 열교환기 모델링)

  • Cha, Jihyoung;Ko, Sangho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.213-217
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    • 2017
  • Since more than 30% of the liquid rocket engine failures occur during the start-up process, and the Space Shuttle Main Engine (SSME) is especially sensitive to small changes in propellant conditions, a 2% error in the valve position or a 0.1sec timing error could lead to significant damage of the engine, simulation modeling of start-up process is important. However, there are many difficulties associated with engine start-up process caused by nonlinear mass flow and heat transfer characteristics associated with filling an unconditioned engine system with cryogenic propellants. In this paper, we modelled a SSME simulation model using partially Computational Fluid Dynamics (CFD) method to solve these problems and checked the performance by comparing with the performance of the simulation model using the lumped method under the state of normal condition.

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